The present application claims priority to Japanese Patent Application No. 2001-256343, filed Aug. 27, 2001. The contents of that application are incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention relates to an arrayed waveguide grating optical multiplexer/demultiplexer and a method for manufacturing the same.
2. Discussion of the Background
Recently, in optical communications, research and development of the optical wavelength division multiplexing transmission has been conducted actively for the way to dramatically increase the transmission capacity thereof, and practical applications have been proceeding. The optical wavelength division multiplexing transmission is that a plurality of lights having a wavelength different from each other are multiplexed and are transmitted, for example. In order to demultiplex the multiplexed light on the receiving side, such optical wavelength division multiplexing transmission systems need optical components which transmit lights having only predetermined wavelengths.
As one example of such optical components, an arrayed waveguide grating (AWG) which is shown in FIG. 12 is known. Referring to FIG. 12, generally, the arrayed waveguide grating is formed as a planar lightwave circuit (PLC) chip. This construction is hereinafter referred to as an arrayed waveguide grating.
Referring to FIG. 12, the arrayed waveguide grating is manufactured by forming a waveguide forming region 10 made from silica-based glass on a substrate made from silicon. The arrayed waveguide grating has at least one optical input waveguide 2 provided side by side, a first slab waveguide 3 connected to the outgoing side of the optical input waveguides 2, an arrayed waveguide 4 including a plurality of channel waveguides (4a) which are connected to the outgoing side of the first slab waveguide 3, a second slab waveguide 5 connected to the outgoing side of the arrayed waveguide 4, and a plurality of optical output waveguides 6 connected to the outgoing side of the second slab waveguide 5. The length of adjacent channel waveguides (4a) are different from each other by a predetermined length difference (xcex94L).
The arrayed waveguide grating is designed and manufactured to have a center wavelength of optical transmission which is equal to a target center wavelength at a predetermined temperature. However, the arrayed waveguide gratings have different center wavelengths of optical transmission and the yield of the arrayed waveguide gratings deteriorates because refractive index, width and thickness of the core vary during manufacturing process.
According to one aspect of the present invention, an arrayed waveguide grating optical multiplexer/demultiplexer includes at least one first optical waveguide, a first slab waveguide, an arrayed waveguide connected to the at least one first optical waveguide via the first slab waveguide, a second slab waveguide, and a plurality of second optical waveguides connected to the arrayed waveguide via the second slab waveguide. The first slab waveguide includes first and second portions which are divided along an intersecting face intersecting an optical path in the first slab waveguide. A slider is fixed at a temperature shifted from a predetermined temperature to compensate a center wavelength difference between a target center wavelength of optical transmission of the arrayed waveguide grating optical multiplexer/demultiplexer at the predetermined temperature and the measured center wavelength of optical transmission of the arrayed waveguide grating optical multiplexer/demultiplexer at the predetermined temperature before the first slab waveguide is divided to the first and second portions, the slider being configured to cause a relative motion between the first and second portions of the first slab waveguide along the intersecting face according to a temperature change.
According to another aspect of the present invention, a method for manufacturing an arrayed waveguide grating optical multiplexer/demultiplexer includes providing an arrayed waveguide grating including at least one first optical waveguide, a first slab waveguide, an arrayed waveguide connected to the at least one first optical waveguide via the first slab waveguide, a second slab waveguide, and a plurality of second optical waveguides connected to the arrayed waveguide via the second slab waveguide. A measured center wavelength of optical transmission of the arrayed waveguide grating is measured at a predetermined temperature. A center wavelength difference between a target center wavelength of optical transmission of the arrayed waveguide grating at the predetermined temperature and the measured center wavelength is found. At least one of the first and second slab waveguides are divided to first and second portions along an intersecting face intersecting an optical path in the at least one of the first and second slab waveguides. A slider is fixed at a temperature shifted from the predetermined temperature to compensate the center wavelength difference such that the slider causes a relative motion between the first and second portions along the intersecting face according to a temperature change.
According to yet another aspect of the present invention, an arrayed waveguide grating optical multiplexer/demultiplexer includes at least one first optical waveguide, a first slab waveguide, an arrayed waveguide connected to the at least one first optical waveguide via the first slab waveguide, a second slab waveguide, a plurality of second optical waveguides connected to the arrayed waveguide via the second slab waveguide. The second slab waveguide includes first and second portions which are divided along an intersecting face intersecting an optical path in the second slab waveguide. A slider is fixed at a temperature shifted from a predetermined temperature to compensate a center wavelength difference between a target center wavelength of optical transmission of the arrayed waveguide grating optical multiplexer/demultiplexer at the predetermined temperature and the measured center wavelength of optical transmission of the arrayed waveguide grating optical multiplexer/demultiplexer at the predetermined temperature before the second slab waveguide is divided to the first and second portions. The slider is configured to cause a relative motion between the first and second portions of the second slab waveguide along the intersecting face according to a temperature change.